I have seen lots of small kids do the movements in different ways, even before they would plausibly have seen the stereotypical dance in media. There is definitely a biological component to it; bending slightly and moving does seem to strengthen the muscles that hold in the pee.

I agree that more research is required. Perhaps the Ignobel Prize could commission some research, since they will probably be awarding the people who do it anyway.

An official IgNobel grants scheme, btw, seems like it might attract a lot of crowdfunding from interested shitposters from all over the internet. I’d definitely throw in a hundo every year.